The invention relates to a stent, particularly a coronary stent, as an intraluminal expansion element, and a method of manufacturing the stent.
An expandable intraluminal element with at least one thin-walled, tubular part (hereinafter referred to as a stent) is known from European patent specifications EP 0 364 787 B1 and
EP 335 341 B1. The surface of the stent is made of net-like open work and contains apertures, which are bounded by strap-like elements of low material thickness extending in straight lines in the longitudinal axial and circumferential directions. The strap-like elements, which can expand in the circumferential direction of the stent, comprise the remains of the tubular wall from which the material in the area of the apertures has been removed.
Another tubular stent, also of net-like structure, is known from international patent application WO 96 03 092 A1. The stent is made up of straps in a meander-shaped arrangement, extending partly in the circumferential and partly in the longitudinal axial direction of the stent. The surface of the stent is similarly made of open-work and has apertures between the straps, in the area of which the material has been removed from the tubular wall.
Stents of this type are expanded during an operation, with outwardly directed forces exerted by a tubular dilator to which high-pressure gas is applied. The stent retains its tubular shape in spite of the deformation, and expands the vessel narrowed by deposits.
For safety reasons deformation of the straps is kept far below a possible danger level, as breakage of a strap would cause its free ends in the region of the breakage to project into the interior of the vessel fitted with the stent. The accompanying risk of the formation of restenosis would not only put the success of the actual operation into question but also endanger the life of the patient.
Thin net structures of the known stent are very susceptible to mechanical damage by exertion of a force, during the period from manufacture to use, and this damage may make them useless of even dangerous. Such damage may not be detected in the non-expanded state and could lead to the final breakage of one or more straps only when the stent is expanded, with the detrimental effects described above.
Known stents also have the drawback that production of their net-like structure is very time-consuming and requires a large outlay on removal of the material cut out of the surface to create the apertures.